Laminate and production method thereof

ABSTRACT

The invention concerns laminates incorporating plastic layers and cellulose fiber layers and a method for the production thereof. The plastic layers and the cellulose fiber layers incorporated in the laminates can be separated intact from each other in aqueous defibering by virtue of a water-soluble polymer layer placed adjacent to the fibrous layer whereby all components of the laminate become recyclable for reuse. The laminates can be produced using extrusion coating/laminating methods. The laminates according to the invention are suited to use as, e.g., wrapper and packaging materials.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is related to a laminate according to the preambleof claim 1.

Such a laminate incorporates at least one first layer comprised ofcellulose fibers, at least one second layer spaced apart the firstlayer, said second layer being comprised of a material which is at leastsubstantially insoluble in water, and at least one third layer which isarranged between said first and said second layer and is capable ofinterbonding said layers.

The invention also concerns a method for producing this laminate, andthe use thereof.

2. Description of the Related Art

Growing environmental problems, limited capacities of dump sites andresultant constraints imposed by the tightening regulatory measuresrequire an increasing degree of recycling in all activities, includingthe packaging sector. Traditionally, paper and paperboard have beenutilized in recycling by way of repulping, that is, defibering of anaqueous waste paper slush. The industry also makes use of repulpingmethods compatible with combination fiber/plastic systems. The goal hasbeen to separate plastic from fibre to the highest degree so that thefibre fraction can be reused.

Prior-art technology suffers, however, from the problem thatconventional combination plastic/fiber products frequently containplastics of low molecular weight (e.g., hot-melt glues), which inaqueous defibering are easily carried through into the fiber reuseprocess and cause impairment of paperboard or paper product produced bysuch a process. Furthermore, detachment of a pure polymer coating orplastic layer from a laminate structure is extremely difficult inaqueous defibering due to the strong adherence of plastic on cellulosefibres. In pulping, such combination materials must be treated sovigorously that the detached plastic is torn into small pieces that,despite the long washing times employed, still contain plenty of paperfibres. The resultant plastic scrap finds hardly any recycling use, andconsequently, its typical fate is combustion or dumping. Finally, thefibre fragmentation into so-called fines is promoted by the elongatedaqueous defibering and relatively high temperature employed in wastepaper furnish preparation process.

To overcome the above-described drawbacks, the plastics industry hasdeveloped polymers soluble in acidic or basic conditions. Such polymershave also been used in different types of laminates and similarproducts.

The EP Patent Specification No. 316,676 describes adhesive layers forlabels etc. that are soluble in basic conditions. The adhesive layersemployed here are copolymers of acrylic or methacrylic acid and acrylateor methacrylate, respectively. The solubility property is designed toaid removal of labels from, e.g., bottles and similar objects.

Polymer layers made of corresponding copolymers have also been used forbinding notebooks and similar items as is described in the EP PatentSpecification No. 330,997. For recycling the pages of such notebooks,soaking in an alkaline aqueous solution is used for unbinding of thepages. A paperboard or paper sheet can be bonded onto such an adhesivelayer so forming the cover or front page of a notebook. Theabove-described polymer-paper laminate is made using wide-slot lip dieextrusion. The publication does not make it clear that the laminatestructure would also be decomposable under alkaline wash treatment orthat this prior-art method would aim at recovery of the polymercomponent.

The EP Published Patent Application No. 88,373 describes the binding ofa book with the help of a polymer layer comprised of a polyvinyl alcohollayer and an adhesive layer. Such a mere PVA layer is soluble in hotwater, of course, but while also being sensitive to moisture, it is notsuited to, e.g., the conditions occurring in the use of conventionalpackages.

The U.S. Pat. No. 3,968,310 describes the coating of a paper web with ahot-melt type composition by way of brush application of saidcomposition onto the web. The applied polymer layer was, in alkalinepulping conditions, detachable from the paper web, which could then berecycled.

The U.S. Pat. No. 5,096,767 discloses a laminate having, placed betweena non-water-soluble polymer layer and the paper web, a plastic layerwhich is alkali soluble at elevated temperature. The laminate isintended for use as a bottle label which in normal conditions ismoistureproof, but detaches from bottle wall in an alkali wash treatmentat approximately 70° C. The alkali wash treatment results in completedisintegration of the laminate, thereby making the laminate incompatiblewith recycling.

As is evident from the discussion above, none of the conventionallaminate embodiments have been able to combine good moisture resistancewith recyclability.

SUMMARY OF THE INVENTION

It is an object of the present invention to overcome the drawbacks ofconventional technology and to provide a laminate which has goodmoisture resistance properties and whose plastic and paper fibre layerscan be separated from each other by repulping, thus making themcompatible with recycling.

The invention is based on the principle of adhering an essentiallynon-water-soluble layer to a cellulose fibre web with the help of ahomogeneous polymer layer that is water-soluble already in neutral pHconditions and at the normal ambient temperature in a factory. Accordingto the invention, to make the non-water-soluble polymer layer adhere tothe cellulose fibre web during the manufacture of the laminate, awater-soluble polymer is employed that, in the molten state, has atleast a relatively high thermal endurance.

More specifically, the laminate according to the invention contains atleast one first layer made from cellulose fibers, at least one secondlayer spaced apart from the first layer, and made from a material thatis substantially non-water-soluble, and at least one third layer betweenthe first and second layers and bonding them together, which third layersubstantially comprises a polymer that is water-soluble at neutral pHconditions and exhibits a decomposition temperature of at least 160° C.

Furthermore, the present invention is directed to a method for producingthis laminate by forming the third layer by extrusion into the nipformed between two webs.

The present invention is also directed to a method using the laminate asa packaging material suitable for packages that are to be recycled.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the basic structure of a paperboard laminate for liquidproduct packaging.

FIG. 2 shows the structure of a wrapper laminate for paper rolls.

FIG. 3 shows the structure of a weather-proof laminate.

FIG. 4 shows the structure of a heat-sealable laminate for the endheaders of paper rolls.

DETAILED DESCRIPTION OF THE INVENTION

The invention provides a recyclable laminate incorporating at least onecellulose fibre layer and typically at least one non-water-solublepolymer layer, or alternatively, a second cellulose fibre layer, saidlaminate having at least one water-soluble polymer layer situatedbetween two or multiple layers so that said water-soluble polymer layeris always immediately adjacent to any cellulose fibre layer.

According to a first preferred embodiment of the invention, the laminatecomprises a cellulose fibre layer, a non-water-soluble polymer layer anda water-soluble polymer layer which interbonds said two former layers.Such a laminate exhibits good heat-sealability as its one surface iscomprised of a non-water-soluble polymer layer.

According to a second preferred embodiment of the invention, thelaminate incorporates two cellulose fibre layers and two (thermo)plasticpolymer layers, the laminate comprising a cellulose fibre layer, awater-soluble polymer layer, a non-water-soluble polymer layer, awater-soluble polymer layer and a cellulose fibre layer, in said order.Such a laminate is particularly suited to applications requiringparticularly high weather resistance.

According to a third preferred embodiment of the invention, the laminateincorporates two thermoplastic polymer layers and a cellulose fibrelayer, the laminate comprising a non-water-soluble polymer layer, awater-soluble polymer layer, a cellulose fibre layer, a water-solublepolymer layer, and a non-water-soluble polymer layer, in said order. Byplacing the non-water-soluble polymer layers as the outer surfaces ofthe laminate, a liquid-tight laminate is obtained suited to applicationsin, e.g., liquid product cartons.

According to a fourth preferred embodiment of the invention, thelaminate incorporates two cellulose fibre layers laminated to both sidesof a water-soluble polymer layer. This type of laminate can be used as apackaging wrapper for, e.g., paper rolls.

In the context of the present application, "a water-soluble polymer"refers to any thermoplastic polymer capable of losing its adhesion, thatis, its adhering capability in water. For the function of the invention,it is therefore essential that said water-soluble polymer detaches inwater from said adjacent layer. In practice, as the water-solublepolymer layer is placed immediately adjacent to the cellulose fibrelayer, water permeates through said fibre layer into the polymer layer,whereby the water-soluble polymer layer is primarily detached from thecellulose fibre layer. For the function of the invention, it issufficient that said layer is separated by the effect of water from thecellulose fibre layer. Said layer can be allowed to continue to adhereto the plastic layer. By suitable control of the conditions, however,the polymer layer can be detached also from the adjacent polymer layer.This occurs, e.g., when the pulping process is continued for asufficiently long time or the non-water-soluble polymer layer is atleast moderately water-permeable.

As is evident from the discussion above, the invention does notnecessarily require that the layer structure of the water-solublepolymer be disintegratable in water nor that it be "soluble" in theconventional sense, but rather, for the function of the embodimentaccording to the invention, it is sufficient that the adhesion can beessentially weakened.

To attain efficient separation of the different layers of the laminatestructure in the aqueous defibering process, it is important that thewater-soluble polymer assumes the form of an at least substantiallyhomogeneous layer in said laminate structure. This is because thepurpose of the laminating polymer layer is to separate the functionalfibre and polymer layers of the laminate from each other so that theselayers are not immediately bonded to each other, but instead, via awater-soluble polymer layer. Here, a "homogeneous" layer refers to sucha layer that, with a possible exception at the borders of the laminate,entirely covers the area of the adjacent layer.

A particularly preferred type of the water-soluble polymer is anextrudable thermoplastic polymer suited to the production of ahomogeneous film with an appropriate thickness. The use of such plasticsmakes it possible to provide the laminate in the final product withmultiple properties particularly required from packaging materials suchas impermeability to moisture vapour, heat-sealability, andprintability. Such advantageous properties could not be attained throughthe use of other water-soluble polymers having a short-chain structuretypically found in so-called "hot-melt" compositions or glues.

The selected polymer material is presumed to tolerate a temperature ofat least 160° C. Namely, this temperature is required for asatisfactorily strong bonding of the polymer onto the cellulose fibreand polymer layers. Since the process temperature in laminatemanufacture practically never exceeds 330° C., this temperature can beset as the upper limit of thermal endurance of the water-soluble polymermaterial.

Further, the polymer must be soluble (in the sense of this term definedabove) in the conditions that are common in a pulper, that is, inessentially neutral pH conditions at the normal factory ambienttemperature. The term "essentially neutral pH conditions" in the contextof this application refers to a pH range from approximately pH 5 toapproximately pH 8 and the term "normal factory ambient temperature" toa temperature range of approximately 10° to 50° C., typicallyapproximately 5° to 30° C. Obviously, many of the polymers usedaccording to the invention are also soluble outside the above limits.

The water-soluble polymer used in the laminate structures according tothe invention can be any thermoplastic polymer (remeltable plastic)which fulfills the above-listed requirements. According to a preferredembodiment, polyvinyl alcohol based polymers which thus containrepeating units according to the formula --(CH(OH)--CH₂)--. Aparticularly suitable polymer is polyethylene grafted with polyvinylalcohol. The polyvinyl alcohol renders the polyethylene the desiredsolubility whose degree can be controlled by varying the proportion ofpolyvinyl alcohol in the polyethene backbone. The proportion of thepolyvinyl alcohol in the grafted polyethylene is typically 0.5 to 50 wt.%, preferably approximately 5 to 30 wt. %. This kind of polymer alonecan already render the final product laminate structure a moderatemoisture vapour barrier capability, because it can tolerate a relativelyhigh ambient moisture content without disintegration. A laminate ofparticularly high moisture vapour barrier capability is attained bycomplementing the soluble polyethene with a non-water-soluble polyethenelayer. The melting point of the described polymer is approximately 120°C. and it can tolerate as an extruded film more than 260° C. at whichtemperature it adheres well to cellulose fibre layers and thermosettingplastic films.

Another vinyl alcohol based polymer which also is preferably suited foruse according to the invention is comprised of the copolymer of vinylalcohol and ethylene having a high proportion of vinyl alcohol residues,typically approximately 10 to 95 wt. %, preferably approximately 30 to80 wt. %. Also in this polymer type the solubility properties can becontrolled by varying the proportion of the vinyl alcohol residues.

Besides the above-listed particularly preferred polymers, also othertypes of water-soluble polymers can be used that contain both monomersof the water-soluble polymer and monomers of the non-water-solublepolymer. Thus, applicable polymers comprise, e.g., the copolymers ofvinyl alcohol and propene, terpolymers of vinyl alcohol, ethylene andpropylene as well as polypropylene grafted with polyvinyl alcohol andthe copolymers of ethylene and propylene grafted with polyvinyl alcohol.

The surface area weight of the water-soluble polymer layer in thelaminate is typically approximately 0.1 to 50 g/m², preferablyapproximately 3 to 30 g/m².

In addition to the water-soluble polymer layer, the laminates accordingto the invention comprise at least one layer comprised of cellulosefibres and at least one third layer which is non-water-soluble. Thelatter can be composed of cellulose fibres or of a polymeric material.The cellulose fibre layers in the laminate can be paper webs, paperboardwebs or similar cellulose based products. The cellulose contained in thelayers can stem from chemical or mechanical pulp which further can bebleached or unbleached pulp. The surface area weight of the materialused for the cellulose fibre layer is typically approximately 10 to 500g/m². Typically, paperboard with a surface area weight of approximately100 to 250 g/m² is employed. The polymer layers of the laminate can beformed from thermoplastic polymers such as olefin, ester, vinyl, styreneor similar polymers. Different types of copolymers are also suitable foruse in the polymer material layers. Example 2 describes such use ofethylvinyl acetate copolymer in a laminate according to the invention.Replacing the polymer or the cellulose fibre material, so-calledregenerated cellulose polymer materials such as cellophane are alsoapplicable. The surface area weights of the polymer layers in thelaminate are in the range of approximately 1 to 250 g/m², preferablyapproximately 5 to 100 g/m². As the cellulose fibre layers and thenon-water-soluble polymer layers form the actual structural componentsin the laminate, they are typically formed to be thicker than thesoluble polymer layer.

For special applications (e.g., juice cartons), the laminates canfurther be provided with metal foils such as aluminium foils. These canbe coated with, e.g., a polyolefin to attain heat-sealability.

The invention also concerns a method for producing a recyclablelaminate, according to which method a water-soluble polymer layer isadhered to the cellulose fibre layer and/or the non-water-solublepolymer layer by the extrusion coating/laminating method. This method iscapable of producing the water-soluble polymer material into such ahomogeneous film for the laminate structure that in a single work stage,together with the other layer elements of the laminate, can be treatedat a sufficiently high temperature (above 160° C.) so thatnon-water-soluble layers (cellulose fibre and polymer layers) can bemade to adhere to the water-soluble polymer.

The method can also be implemented using extrusion coating, thewater-soluble polymer being produced by extrusion into a sheet which isadhered to the surface of the cellulose fibre web. The second,non-water-soluble layer of the laminate, which is adjacent to the otherside of the water-soluble layer is here adhered at another stage.

Preferably, however, the method is implemented using extrusionlaminating which operates by feeding said polymer sheet from theextruder between at least two webs and then adhering it to these. One orboth of the webs can be formed by a cellulose fibre web and/or thesecond polymer material. The method is implemented particularlyadvantageously using the coextrusion technique in which all polymerlayers of the laminate are produced in a single stage in a coextruder.

According to the first preferred embodiment of the invention, a laminatecomprised of a cellulose fibre layer, a water-soluble polymer layer anda non-water-soluble polymer layer (in said order) are producedpreferably using two-layer coextrusion. The combination of thewater-soluble polymer film and the non-water-soluble polymer filmproduced by coextrusion is applied onto the cellulose fibre web at atemperature above 160° C. According to a second preferred embodiment ofthe invention, the five-layer laminate having the innermost layer madefrom a non-water-soluble polymer is produced in a similar way by usingthree-layer coextrusion, the polymer materials of the laminate beingapplied as coextruded films in the nip formed between two cellulosefibre webs. According to a third preferred embodiment, the five-layerlaminate having the innermost layer made from a cellulose fibre web isproduced by pair-wise coextruding the polymer layers to be applied toboth sides of the cellulose fibre web.

The laminates according to the invention can be produced into packagingmaterials, bags, wrappers, moisture-proof papers and similar productsexhibiting moisture vapour barrier capability. As the laminate accordingto the invention offers wide variability, the required properties of thefinal product can be attained without compromises. This is particularlyimportant for the use of the cellulose fibre/polymer layer laminates infood product packages whose recycling rate is growing rapidly, yetwithout compromising their barrier properties to moisture, gases andeven liquids. Paperboard grades for liquid product packages, e.g., milkand juice cartons, are preferred applications for the pulping-compatiblelaminates described above.

A typical example of the pulping-compatible laminate product accordingto the invention is also a paper roll wrapper formed by coextrusionlaminating a water-soluble polyethylene layer between two liner boardsheets. The end headers for such wrapper are made from paper webs coatedaccording to the invention. Such paper webs coated according to theinvention are produced using conventional coextrusion techniques andthey are heat-sealable, which further expands the application range ofthe recyclable cellulose fibre/polymer laminates according to theinvention in industry, particularly in the packaging branch.

The invention offers significant benefits. Particularly, laminatesaccording to the invention are entirely recyclable, the cellulose fibreand polymer layers inclusive, which, in accordance with the abovedescription is based on the concept of having the cellulose fibre layercoated with a polymer layer exhibiting loss of adhesion through soakingin water. If a polymer layer naturally exhibiting strong adhesion to thefibre material is adhered to this water-soluble polymer layer, suchinsoluble polymer layer is detached in the form of a sliced film alongwith the water-soluble layer detaching from the cellulose fibre layerduring soaking. By virtue of the water-soluble polymer layer, thepulping of laminates according to the invention is thus converted into arapid, efficient and thereby energy-saving method of reclaiming andrecycling the laminate, both the fibre layer and plastic layer elementsinclusive. During the pulping of the laminates, the separated polymerparticles retain a larger shape than those obtained from conventionallaminates, thus providing easier reclaiming for reuse.

In the following, the invention will be examined in greater detail withthe help of exemplifying embodiments illustrated in the attacheddrawing. It should be pointed out that that the descriptions of thediagrams and exemplifying embodiments below are intended to elucidatethe applications of the invention, and they must by no means beinterpreted to limit the scope of the invention. The examples coverlaminates suited for industrial sector use in the production of, e.g.,bags, wrappers and moisture-proof papers.

FIG. 1 illustrates the structure of a paperboard laminate for liquidproduct cartons. Such a laminate comprises five layers, thewater-soluble polymer layers 1 being arranged at both sides of acellulose fibre layer 2. Non-water-soluble polymer layers 3, 3' arefurther arranged as the outer (3) and inner (3') layers, respectively,of the laminate.

In the embodiment according to FIG. 2, the laminate comprises threelayers, namely cellulose fibre layers 4 and an interbonding polymerlayer 1 made of a material soluble in water.

FIG. 3 illustrates a five-layer laminate having the outer layers 4comprised of cellulose fibre web, the inner layer 5 made of anon-water-soluble polymer and the interbonding layers 1 made of amaterial soluble in water.

FIG. 4 illustrates a laminate having a structure according to the basicembodiment of the invention, in which the water-soluble polymer layer 1interbonds the cellulose fibre layer 4 and the non-water-soluble polymerlayer 6.

The production of the laminates shown in the diagrams are described indetail in the following examples:

EXAMPLE 1 Production of five-layer paperboard laminate for liquidproduct cartons

A laminate according to FIG. 1 was produced having its innermost layermade from paperboard 2 with a basis weight of 300 to 320 g/m². Awater-soluble polymer layer 1 made from a copolymer of polyethene andpolyvinyl acetate was adapted to both sides of this paperboard layer 2.To act as the outer surface polymer layer 3, over the water-solublepolymer layer was adapted a polyethene layer with a surface area weightof 10 g/m². Also made from polyethene, the inner surface layer 3' had asurface area weight of 25 g/m². In the laminate according to FIG. 1, thepolyethylene layer with the water-soluble polymer layer adhering to itwere coextruded onto the paperboard layer 2, and so was applied to theinside surface of the paperboard the polyethylene layer with thewater-soluble polymer layer adhering to it.

EXAMPLE 2 Production of three-layer wrapper laminate

A paper roll wrapper laminate was produced by extrusion laminatinghaving a structure illustrated in FIG. 2. The innermost layer of thewrapper laminate, that is, the water-soluble polymer layer 1 had asurface area weight of 30 g/m², while UG Kraft paper layers 4 placed toboth sides of it had a surface area weight of 60 g/m² each. Thewater-soluble polymer layer was made from ethylene polymer grafted withpolyvinyl alcohol, produced by Neste Oy with the trade name NCPE 0210,having a melt index of 6.0 g/10 min and density of 1140 kg/m³. The layersolubility in water could be controlled by varying the polyvinyl alcoholcontent in the polyethylene. The UG Kraft paper grade employed in thewrapper was a kraft grade produced by Yhtyneet Paperitehtaat Oy.

The product was made by extrusion laminating at 240° C. The layersadhered well to each other, that is, the mutual adhesion was good. Afteruse as a roll wrapper, the product was pulped at approximately 25° C. inan aqueous defibering unit adjusted to neutral pH conditions. The paperfibres separated entirely intact from each other in a 10 min treatment.The pulping of a conventional paper/polyethylene/paper combinationlaminate typically requires a two- to three-fold time and yet leaves thefibres contaminated with plastic.

EXAMPLE 3 Production of five-layer weatherproof laminate

A laminate product according to FIG. 3 with a particularly highweather-proofness was produced using three-layer coextrusion. Theinnermost layer of the laminate formed by the non-water-soluble polymerlayer 5 had a surface area weight of 30 g/m², the water-soluble polymerlayers 1 applied to both sides of the innermost layer had a surface areaweight of 5 g/m². The outermost layers were formed by UG Kraft paperlayers 4 (with a surface area weight of 125 g/m² each). Thenon-water-soluble polymer grade employed was a polyethylene-basedplastic produced by Neste is Oy with the trade name NCPE 0414, having amelt index of 1.7 g/10 min and density of 927 kg/m³. The water-solublepolymer NCPE 0210 adheres remarkably well to this insoluble polymer. TheNCPE 0414 polymer grade confers the product good moisture vapour barrierproperties and the product is found to store without degradation even inhumid conditions. The fibres separate easily in aqueous defibreing, andby virtue of the water-soluble polymer layers, the innermost layer staysas a pure layer of plastic easily reclaimable and recyclable for reuse.

EXAMPLE 4 Production of three-layer packaging laminate

An easily heat-sealable laminated paper roll end header was producedthrough two-layer coextrusion (FIG. 4). The center layer 1 was, madefrom water-soluble polymer NCPE 0210 having a surface-area weight of 5g/m². The heat-sealable polymer layer 6 was made to a surface areaweight of 35 g/m² from a 9% blended ethylvinyl acetate copolymer EVANCPE 5009 by Neste having a melt index of 8 g/10 min and density of 929kg/m³. Finally, the laminate had a base layer 4 made from UG Krafthaving a basis weight of 150 g/m².

Also in this example the adhesion of the outer polymer layer to the basepaper layer was rapidly weakened in aqueous defibreing by virtue of thewater soluble layer of NCPE 0210, thus permitting the separation of thelaminate into intact plastic and paper components suitable for reuse.

What is claimed is:
 1. A recyclable laminate, comprising:(A) at least one first layer made from cellulose fibers; (B) at least one second layer spaced apart from said first layer, wherein said second layer is made from a substantially non-water-soluble polymer material; and (C) at least one third layer between said first and said second layers which directly bonds to said first layer and bonds said first and second layers to each other, wherein said third layer comprises a polymer which is water-soluble at neutral Ph conditions and exhibits a decomposition temperature of at least 160° C.
 2. The laminate as defined in claim 1, wherein said polymer has a decomposition temperature within the range from 160° to 330° C. and is suitable for processing by extrusion.
 3. The laminate as defined in claim 1, wherein said polymer is water-soluble within the pH range from 6 to 8 and at a temperature in the range from 5° to 50° C.
 4. The laminate as defined in claim 1, wherein said polymer is selected from the group consisting of polyethylene grafted with polyvinyl alcohol and a copolymer of vinyl alcohol and ethylene.
 5. The laminate as defined in claim 4, wherein said polymer is polyethylene grafted with polyvinyl alcohol, and wherein the proportion of the polyvinyl alcohol in the polyethylene is in the range from 0.5 to 50 wt. %.
 6. The laminate as defined in claim 1, wherein said second layer (B) comprises a non-water soluble thermoplastic polymer.
 7. The laminate as defined in claim 6, wherein said second layer comprises polyethylene.
 8. The laminate as defined in claim 1, wherein said second layer comprises a cellulose fiber layer.
 9. The laminate as defined in claim 1, wherein said laminate comprises two first layers and two third layers, and comprises a cellulose fiber layer, a water-soluble polymer layer, a non-water-soluble polymer layer, a water-soluble polymer layer, and a cellulose fiber layer, in that order.
 10. The laminate as defined in claim 1, wherein said laminate comprises two second layers and two third layers, and comprises a non-water-soluble polymer layer, a water-soluble polymer layer, a cellulose fiber layer, a water-soluble polymer layer, and a non-water-soluble polymer layer, in that order.
 11. The laminate as defined in claim 1, wherein said non-water-soluble material of the second layer and the cellulose fibers of the first layer can be separated from each other by aqueous defibering of the laminate in neutral pH conditions, whereby the material components of the first and the second layer can be reclaimed separately from each other in the form of substantially homogeneous layers.
 12. The laminate as defined in claim 6, wherein said water-soluble material component can be separated by aqueous defibering of the laminate from said cellulose fiber layer whereby said water-soluble material component continues to adhere to said non-water-soluble polymer layer.
 13. The laminate as defined in claim 1, wherein said laminate is produced using the extrusion coating or extrusion laminating method.
 14. A method for producing the laminate defined in claim 1, comprising:extruding at least one material selected from the group consisting of said water-soluble polymer, and said non-water-soluble polymer material into at least one sheet; and adhering said sheet onto at least one layer selected from the group consisting of said cellulose fiber and said non-water-soluble polymer by heating to a temperature sufficiently high to cause said water-soluble polymer of said sheet to adhere to said layer.
 15. The method as defined in claim 14, wherein said extruding comprises extruding a sheet of said water-soluble polymer layer and a sheet of said non-water-soluble polymer layer onto said cellulose fiber layer.
 16. The method as defined in claim 14, wherein said extruding comprises extruding a sheet of said water-soluble polymer layer into a nip formed between two cellulose fiber layers.
 17. The method as defined in claim 14, wherein said extruding comprises extruding a sheet of a polymer film combination comprising a non-water soluble polymer center layer coated on both sides by water-soluble polymer layers into the nip formed between two cellulose fiber layers.
 18. The method as defined in claim 14, wherein said extruding comprises extruding a sheet of a polyethylene polymer layer grafted with polyvinyl alcohol into the nip formed between two base layers.
 19. A packaging material suitable for recycling comprising the laminate defined in claim
 1. 